Potentiometer



July 26, 1955 Rz L, REID 2,714,147

POTENTIOMETER Filed Nov.' 29, 1952 `.{ILIIIIII//IlllI4 (y E i6 Z5! 25 i1 i4 1W -2. If

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JNVENTOR. H0857?? L F575; BY:

AfroA/IP;

l claim as my invention:

1. A potentiometer comprising a dielectric frame, a first terminal stationarily fixed in said frame, an elongated resistor element axially reciprocable in said frame, a 'second terminal stationarily fixed in said frame and peripherally, slidably engaging said resistor element, electricalconductor means yieldably connecting said first terminal with one end 'of said resistor element, and adjustment means for shifting said resistor element axially, relative to said second terminal, through a stroke substantially equal to the length of said resistor element while said second terminal maintains sliding engagement with said resistor element.

2. A potentiometer comprising a dielectric frame, a first terminal stationarily fixed in said frame, an elongated resistor element axially reciprocable in said frame, a second terminal stationarily fixed in said frame and pcri'pherally, slidably engaging said resistor element, electrical-conductor means yieldably connecting said first terminal with one end of said resistor element, adjustable means for shifting said resistor element axially relative to said second terminal while remaining in sliding engagement therewith, a third terminal fixed to said frame, and electrical conductor means yieldably connecting said third terminal and the other end of said resistor element.

3. The device of claim 2 in which the first said conductor means comprises a coiled spring confined between said first terminal and said one end of said resistor element, and the second conductor means comprises a second coiled spring confined between said third terminal and said other end of said resistor element.

4. A potentiometer comprising a dielectric body, a first terminal stationarily fixed in said body, an elongated resistor element axially reciprocable in said body, a second terminal stationarily fixed in said body remote from said tirts terminal and slidably engaging the periphery of said resistor element, a coiled, electrically-conductive spring confined between said first terminal and the adjacent end of said resistor element, and means for axially adjusting said resistor element relative to said rst terminal while maintaining said second terminal in peripheral engagement with said resistor element.

5. The device of claim 4 in which said resistor element is peripherally threaded and said second terminal operatively engages said thread whereby rotation of said resistor element axially shifts said resistor element, such structure comprising the said means for axially adjusting said resistor element.

6. The device of claim 4 including a third terminal stationarily fixed in said body remote from said second terminal and on the side thereof opposite said first terminal, and a coiled spring confined between said third terminal and the adjacent end of said resistor element.

7. A potentiometer comprising a body of dielectric material having an axial bore therethrough and a radiallyopening aperture near the midpoint thereof. an abutment member of conducting material stationarily fixed near one end of said body transaxially to the bore therein, an elongated resistor element axially reciprocable in said body bore, a contact carried by said body and enterable through the radial aperture therein to resiliently and slidably engage the periphery of said resistor element, a coiled spring confined in said body bore between said abutment member and the adjacent end of said resistor element, and means for axially adjusting said resistor element relative to said abutment member.

S. The device of claim 7 in which the last said means comprises a plate stationarily fixed on said body to close one end of said bore and having a threaded aperture therein substantially coaxial with said bore, and a screw operatively connected to said resistor element and threadedly received through the aperture in said plate.

9. The device of claim 7 in which said resistor element is formed with a peripheral thread and said contact is resiliently held in operative engagement with such thread, such structure comprising the said means for axially adjusting said resistor element.

10. The device of claim 7 comprising a second abutment member of conducting material stationarily fixed near the other end of said body transaxial to the bore therein, and a second coiled spring confined in said body bore between said second abutment member and the adjacent end of said resistor element.

11. The device of claim 10 in which each of said abutment means comprises a pin passing transaxially through said body and projecting beyond said body to form an electrical terminal and said contact comprises a split ring having a portion thereof turned to follow a chord of the ring, said portion, when said ring encircles said body, passing through the radial aperture formed therein to resiliently engage the periphery of said resistor element.

12. A potentiometer comprising a body of dielectric material having an axial bore therethrough and a chordal slot opening through the periphery near the midpoint thereof, a split ring of electrically-conductive material surrounding said body and having a portion turned to follow a chord thereof, such portion passing through the chordal slot in said body, an elongated resistor element axially reciprocable in the bore in said body and peripherally engaged by said ring portion, an electrically-conductive first pin transaxially penetrating said body near one end thereof, an electrically-conductive second pin transaxially penetrating said body near the other end thereof, a first coiled spring confined in said body bore between said first pin and the adjacent end of said resistor element, a second coiled spring confined in said body bore between said second pin and the adjacent end of said resistor element, a cap closing one end of said body and having a threaded aperture therein substantially coaxial with said body bore, and a screw operatively connected to said resistor element and threadedly received through the aperture in said cap.

13. A potentiometer comprising a body of dielectric material having an axial bore therethrough and a chordal slot opening through the periphery near the midpoint thereof, a split ring of electrically-conductive material surrounding said body and having a portion turned to follow a chord thereof, such portion passing through said chordal slot in said body, an elongated resistor element axially reciprocable in the bore in said body and formed with a peripheral thread therein, said ring portion being resiliently urged into threaded cooperation with said resistor element thread, a first electrically-conductive pin transaxially penetrating said body near one end thereof, a second electrically-conductive pin transaxially penetrating said body near the other end thereof, a first coiled spring confined in said body bore between said first pin and the adjacent end of said resistor element, a second coiled spring confined in said body bore between said second pin and the adjacent end of said resistor element, and means for rotating said resistor element relative to the chordal p0rtion of said ring to shift said resistor element axially in said body bore.

References Cited in the file of this patent UNITED STATES PATENTS 1,589,501 Wohl June 22, 1926 FOREIGN PATENTS 246,189 Great Britain Jan. 28, 1926 246,944 Great Britain Feb. 11, 1926 

